You need to design security changes that provide maximum protection for customer data and courier assignments.What should you do？（）

A. Create a separate domain for courier authentication
B. Implement smart card authentication for business office users and couriers， upgrading client operating systems as needed. Modify the Web kiosks to require smart card presence for continued access
C. Modify the Default Domain Policy Group Policy object （GPO） so that couriers must use complex user account passwords. Require all couriers to change their passwords the next time they log on to the Web application
D. Use Encrypting File System （EFS） to encrypt all files that contain customer data